264 
EXPERIMENTS ON THE 
also any pressure on the sole when it is thin. Many heavy horses’ 
feet shelve out under their great weight, and the sole may be 
forced unevenly on the shoe and cause lameness; or when the 
shoe is put on, owing to this shelving of the hoof, the shoe may 
be forced unevenly, or in a particular point, upon the thinned sole, 
and, forcing it up, cause pain and lameness. This may be sup¬ 
posed to be descent of the sole ; but 1 do not consider it to be so, 
although in flat or pumiced feet, as a matter of course, the sole does 
descend ; but even in these cases I have seen great benefit from a 
support or bearing on the sole, although at first producing incon¬ 
venience. I may also remark, if it were the nature of the foot 
to expand at its lower circumference at the quarters at each 
step, how comes it that any sudden attempts by shoeing to cause 
this action of the foot will produce the greatest inconvenience to the 
animal; any unnatural forcing out of the quarters giving quite as 
much pain as pressing them inwards 1 
10 th Experiment, 
On the dead fore foot of a cart-horse. 
The foot was of good quality, and moderately concave. The 
horny sole was entirely removed, and a shoe laid even to the heels 
applied ; and the piece of wood fitted to the coronet-bone as before, 
and pressure applied in a powerful vice at the opposing surfaces of 
the shoe and the wood, with a view particularly of watching the 
sole whilst under pressure. Candles were held in various directions, 
and the handle of the vice turned backwards and forwards. 
Result .—I could not detect any descent whatever of the sole ; 
but the frog evidently descended opposite to the navicular bone, 
though it did not alter in any way at its base. The descent of the 
frog opposite to the navicular bone appeared to be, at the greatest, 
a quarter of an inch, beyond which it did not seem to descend. 
11 th Experiment. 
The same foot used as in the last case, and it was sawn through 
in the direction of the cleft of the frog, making a complete section, 
thus exposing the internal parts. A shoe was nailed to the half of 
the foot, which was then put into a vice, and the coronet-bone and 
the shoe made the opposing surfaces. On pressure being applied, 
there was a beautiful elasticity of parts visible; the coronet-bone 
first pressed on the coffin-bone, and as the former yielded back¬ 
wards and downwards it pressed on the navicular-bone, which im¬ 
mediately descended, and with it the horny frog opposite to the 
navicular-bone. The elastic tissue round the coronet swelled out, 
and the base of the heel felt firm and rigid, as though distended. 
